Rattle from the motor....
 

I have a 1983 SE with the 12a motor. When cold, my motor was rattling/scraping a bit. To me it sounded like an apex seal possibly tapping and scraping on the drivers side of the motor (keep in mind this is my first rotary but I've always done my own work on cars so I COULD be wrong). Once warmed up, the sound and vibration was completely absent. I put in some 2 stroke oil in the fuel tank (4 ounces in 1/2 a tank), and started it cold today (it's 35 degrees F here), and the sound and vibration is gone it seems. How worried should I be? Any other possibilities that would make a definite scraping sound with a very noticible rattle and shake in the motor?

If you can, post a sound clip, that would help with a diagnosis. Since adding pre-mix helped, check the operation of your MOP system, particularly the position and movement of the MOP rod. I find it odd that adding pre-mix helped. Check your timing, dizzy cap/rotor, plugs, plug wire, the general tune up stuff. Then check the fan belts and see if there's any play the pulleys.

Does the rattle stay throughout the rpm range or is it only during idle when cold?

Rattles can indicate pinging due to incorrect timing or fuel mixture. Also post your mods. Btw, there's no such model as an 83 SE.?

Ah, my model has the limited slip rear with disc brakes, I thought that was SE.
Anyhow, I cant get a good sound clip because all I have is a crappy cell phone camera. The MOP is disconnected I believe. It does leak a bit of oil from where I BELIEVE it is supposed to go (passenger side, bottom/front of motor).
The sound was only at idle, and only when not warmed up fully. If I took it out the sound and vibration would go away and did not increase. Revving the motor a bit at idle would smooth it out but would return at idle speed.
Mods are: street port, RB header, full exhaust (2 1/4", unknown brand with presilencer and RB tip muffler), hotter coils (ACCEL IIRC), light flywheel and new clutch. All was done by previous owner so I don't know about the quality of the work but if the internals are put together the same way as some of the stuff up top it's amateur at best.

oh, and there was the very distinct sound of metal-on-metal scraping at a regular interval. which is why I believe the apex seals are touching the case.

** I put in some 2 stroke oil in the fuel tank (4 ounces in 1/2 a tank), and started it cold today (it's 35 degrees F here), and the sound and vibration is gone it seems.**

Are youy saying you don't ALWAYS use 2-stroke oil? Or that you added more than was already there? (If your OMP is blocked off, you HAVE to mix oil ALL the time.)While trying to tune mine with the weber 45 I have, I got that same noise, but more at a higher rev. Mine was a combination of timing and poor mixture, Also it sounds like I have a water pump going out, you might look at those too.

Assuming you still have the Nikki carb, check the timing, see if the vacuum lines are connected to the dizzy and check the settings on the carb. What is your warm engine rpm?

If the MOP is disconnected, are you pre-mixing? There is a rebuild kit for the MOPs. I would do that and connect it back up, unless you're running an after market carb that has no provision for the MOP rod. Then buy/make a MOP block off plate and pre-mix.

Lsd units came in the GSL and the SEs.

Well, I just got the car and haven't run it much. I don't know if the kid that had the car before me used it or not, there was none in the car which leads me to believe not. And now that you mention it, I did retard the timing a bit yesterday as it was fully advanced. (initial, not currently connected to the vacuum advance). And I leaned out my idle mixture as I could smell fuel badly enough to burn my eyes. So possibly I tuned it out? Or should I be worried still?

Im running the Nikki 4 barrel, but it is SERIOUSLY beyond shot. The kid I bought the car from used JB weld in most of the vacuum ports and capped most of the rest (rats nest removed and so is all the smog crap). I'll be getting a bare Nikki ordered in a few days from Sterling.

Use a timing light and check the timing first. PO may have it in a bit off. Once timing is good, look/search here for "nikki tuning" I don't remember the thread, but theres one that gives you a baseline to start with. Be sure you are somewhere in the same playing field tuning wise. Check cap and rotor,you said new coils, is the dizzy connected to all wires? PO may have done some ignition mods too. Also if you still have the emissions, check for vac leaks. If you try to tune out of time or with leaks etc. you'll have to do it again when you fix em.

No emissions or A/C is on the car. Vacuum leaks are a non-issue. I actually used the Nikki guideline last night to get me in the right ball park. From what you guys are saying maybe it isn't so much the 2 smoke oil in the fuel but possibly tuned halfway correctly (I put in the oil after I tuned using the guidelines in this forum). I've gotten it running and starting reliably because of this forum, you guys are great. Thanks alot, I'm much less worried now.

Thought you guys might like to see what I'm using for air and fuel delivery. Notice the mechanics wire. NOT SHOWN: JB Weld in almost every vacuum port on the thing.
http://i50.tinypic.com/263ix75.jpg

I notice several things not connected right off. The vac line to the charcoal canister, the vac line to the brake booster, the 'teeter totter' on the carb is not connected and the egr needs to be removed and a block off plate installed. I hope that hooked wire isn't your throttle cable.

^ACV or air control and check valve (it makes things easier in a search)

Yes, remove the ACV and replace with a block off plate. Buy from Racing Beat/Mazdatrix or make your own.

Lol, no, that loose cable is my rigged up choke. What is the teeter totter you're talking about and what does it do?
Keep in mind, this was all the prior owner's doing, and will be far more sorted once I get my Sterling carburetor. Since I'm sure you guys love seeing horror pictures, here is a full shot under the hood. Notice the lack of the engine fan and if you look close enough I think you can see the JB Weld job on the radiator and the vacuum advance isnt connected. I see a lot wrong here, help me find more. http://i50.tinypic.com/1hbhhi.jpg

um if the MOP fails, or you don't use premix, the engine WILL make noises.

hard to describe, sounds like scraping?

if that's what it is, its bad.

Yeah there was a definite scraping, not horrible sounding, faint but present. I put in the premix, adjusted the carburetor as outlined on the Sterling website and retarded my timing a bit. In doing all this the motor has gone from not wanting to stay running and making the tapping/scraping noise to purring like a kitten. It looks like hell underhood but still has the balls to get ass out in second gear.
If the motor DOES take a turn for the worse and dies, what is a fair price for a replacement 12A? I have absolutely no interest in any sort of a swap, this one is staying 12a as long as I own her.

You're also missing the fan shroud. Where in KS are you located? I'm an hour north of KC and may be able to help you out if you aren't too far away. Download the factory carb manual from the links in the FAQs. In the manual will you will find exploded diagrams of t showing how the teeter totter spring sits in the saddle. Don't recall the proper term names for the parts.

I can probably help you out with some of the missing parts, but you will need a series of close up pics to see what all is wrong/missing.

I'm in Hays, Kansas. I appreciate the offer man. Like I said though, I'm getting a Sterling carburetor and I'm just limping it along until then. I can, however give you another shot. Keep in mind that any vacuum port that looks open is filled with epoxy. I went at the carburetor for quite a while with a can of ether before I was satisfied that it is, in fact, air tight.
http://i45.tinypic.com/be93l4.jpg

I hope you didn't epoxy the vac line to the brake booster, the large one with the 3/8" hose. It will cause a major vac leak if left open to the intake manifold and not connected to the brake booster will cause braking to need a considerable effort.

I'm not entirely sure which one that is without going out and looking at it, but the brakes seem like they're power units. I drive it around at night after work getting my tuning issues sorted and all before I put it on the road as my daily driver. I've had no issues with the brakes at all. they seem to be functioning as good as any other car I've ever had with power brakes. Stops on a dime, every time :)

this may be the problem. may have sucked some of that into the engine. always use those rubber caps.

you need to keep pre mixing.

Oh, I will. Anything to keep her running as long as possible.
Started her today and it was about 30 degrees F. Had to use ether to start because my choke is disconnected but the rattling seems gone at all rpm.

I suggest you change the oil and filter it through a filter that's used for automotive paint mixing. Also cut open the oil filter and inspect it for metal particles. If you find any brass shavings, plan for a rebuild, soon.

That's a freaking great idea. I'll get on that as soon as it gets warmer out.
Until then, I'm going to hope for the best and plan for the worst.
If it eats itself before that....well, it was going to happen sooner or later I guess.
For now though, it seems fine and happy. Time and RPM will tell the rest of the story.